Search

This paper proposes a new design for line-start operation of synchronous reluctance motors. In the past years, synchronous reluctance motors have been studied by many researchers. Due to high efficiency, they have gained increasing interest because in the synchronous operation, there is limited losses in the rotor. On the other hand, line-start operation of the synchronous reluctance motors is an important challenge that can make this type of the motors popular in many applications. However, line-start operation techniques should not considerably affect the steady-state characteristics of the motor. In the proposed design, the arrangement, size and shape of the rotor conductor bars are designed based on the rotor magnetic circuit difference between induction and reluctance synchronous motors. Complete assessment of the motor parameters are examined using finite element analysis. The proposed structure improves the starting characteristics of the motor. Moreover, power factor of the proposed motor is slightly increased in comparison to that of conventional line-start synchronous reluctance motors. The results obviously show effectiveness of the proposed line-start operation strategy for the synchronous reluctance motors. Finally, experimental verification are also included to confirm the finite element analysis results. [ABSTRACT FROM AUTHOR]

As electric vehicles (EVs) continue to acquire prominence in the transportation industry, improving the outcomes and efficiency of their propulsion systems is becoming increasingly critical. Switched Reluctance Motors (SRMs) have become a compelling option for EV applications due to their simplicity, magnet-free design, robustness, and cost-effectiveness, making them an attractive choice for the growing EV market. Despite all these features and compared to other electrical machines, SRMs suffer from some restrictions, such as torque ripple and audible noise generation, stemming from their markedly nonlinear characteristics, which affect their productivity and efficiency. Therefore, to address these problems, especially the torque ripple, it is crucial and challenging to enhance the performance of the SRM drive system. This paper proposed a comprehensive review of torque ripple minimization strategies of SRMs in EV applications. It covered a detailed overview and categorized and compared many strategies, including two general categories of torque ripple mitigation encompassing optimization design topologies and control strategy developments. Then, focused on control strategy improvements and divided them into torque and current control strategies, including the sub-sections. In addition, the research also provided an overview of SRM fundamental operations, converter topologies, and excitation angle approaches. Last, a comparison between each method in torque control and current control strategies was listed, including the adopted method, features, and drawbacks.

Switched reluctance motors (SRMs) face challenges in achieving high performances in terms of the power factor, torque per ampere, and torque ripples. Although several parameters impact their performance, magnetic saliency has a significant impact. This paper presents a study on the influence of the saliency ratio on the performance of switched reluctance motors. A detailed design procedure for a mid-drive electric motor for a high-performance electric bike is presented. A systematic methodology is adopted to estimate the power rating for desired vehicle performance while considering the vehicle's mechanical and aerodynamic parameters. Additionally, the paper discusses and analyzes the design of two SRM motor configurations with different rotor poles (6/4 and 6/10) while performing magnetostatic analysis for generated torque validation. A parametric study is performed on the 6/10 SRM design for further improvement in the torque profile while keeping the same fill factor and electrical loading. Furthermore, the transient analysis in Ansys Maxwell 2D for both SRMs confirms the designed performance. The results shows that the SRM with higher rotor poles (6/10) is a better choice. [ABSTRACT FROM AUTHOR]

Because of their attractive features, switched reluctance motors (SRMs) are strong candidates with real chances on the market for several industrial applications including vehicle propulsion. However, the SRMs suffer from torque ripple and associated acoustic noise. A proper control algorithm can handle torque ripples to an accepted limit. However, the internal faults in stator windings of SRMs deteriorate not only the performance of control algorithm but also the output power, efficiency, and noise (torque ripple). They cause fast degradation of motor lifetime. Therefore, this paper introduces a novel method to counteract the internal faults in winding of SRMs. A new simulation method for SRMs including the capability of interturn faults is introduced. The proposed novel interturn fault tolerant control (FTC) is achieved based on average torque control (ATC) algorithm. The switching angles are optimized smartly providing a less complicated control algorithm to fit properly with the industrial platforms. The simplicity of overall control algorithm is still functional. The performance of proposed FTC is evaluated compared to healthy motor conditions as well as faulty conditions. The results show the superior performance of the proposed control.

This research presents an improved direct instantaneous torque controller (DITC) for switched reluctance motors (SRMs). It incorporates a novel adaptive real-time commutation mechanism. The proposed method can effectively enhance the torque profile and efficiency of the machine by proper real-time adjustment of both the turn-on and the turn-off angles. First, an initial value of the turn-on angle is selected to achieve the highest torque generation capability. Then, with a real-time adjustment around the pre-selected initial angle, the instantaneous torque error can be further compensated. Hence, the torque ripple is minimized.Regarding the turn-off angle, an initial value is selected to satisfy the minimum required conduction angle of SRM. Then, this value is continuously adjusted at each electrical cycle by utilizing a phase current detector to force the outgoing phase current to decay to a less effective value before the negative slope of the inductance profile. Therefore, this prevents serious negative torque generation. The proposed strategy fully utilizes the torque generation capability of the motor with a minimized torque ripple, besides the phase currents, are generated in optimal conduction range to enhance the motor efficiency. The simulations and experiments have been carried out on a 3-phase 750 W 12/8 SRM to validate the proposed method's feasibility and effectiveness.

Here, the authors propose two new Permanent Magnet (PM) embedded linear switched reluctance motors; one is a modular linear hybrid reluctance motor (MLHRM), and the other one is a segmental linear hybrid reluctance motor (SLHRM). Both structures employ PMs between the side teeth of the modules/segments. The main contribution of the PMs is to increase the air‐gap flux density, which results in an enhanced thrust, and decrease the magnetic saturation in iron parts. The magnetic equivalent circuit model is used to demonstrate the positive effect of inserting PMs in the MLHRM and SLHRM compared to their PMless counterparts. The optimal pole number and design procedure are illustrated. The simulation results are obtained in terms of static thrust, flux linkage, flux density distributions, and steady‐state current and thrust. The results show that the proposed MLHRM and SLHRM offer a higher thrust and lower current compared to their PMless form. Also, the PMs decrease the root mean square (RMS) current under the steady‐state performance of the motors, in which a higher thrust is produced with a lower RMS current. Finally, the MLHRM and SLHRM are fabricated and the test results are obtained and compared with the simulations, which illustrate a satisfactory agreement. [ABSTRACT FROM AUTHOR]

Low-cost photovoltaic-powered elevators (PVPEs) have gained ever-increasing attention in the last few years for their advantages in terms of renewable energy and low maintenance costs after installation. In this paper, four high-step-up DC-DC converters for low-voltage sources such as solar photovoltaic, fuel cells, and battery banks are proposed. Their performances are evaluated in terms of optimal capability and high reliability. Among the four proposed architectures, the bootstrap converter is selected for its ability to restrict losses and other redundant parameters. The proposed converter drives the inverter-driven switched reluctance motor (SRM) assembly through a directly coupled method, which eliminates the need for battery banks while aiding in cost reduction. The prototype model is implemented, and results are validated, showing promising performance and thus being very efficacious for application to low-cost PVPEs.

The double salient pole structure of Switched Reluctance Motor (SRM) makes its electromagnetic field exist nonlinear saturation characteristics, resulting in its large torque pulsation in operation, so it is difficult to achieve speed regulation smoothly by traditional control methods. In view of this problem, a sliding mode control strategy which is based on synchronous transmission technology was proposed.Firstly, the basic structure of switched reluctance motor was analyzed, and the mathematical model of mechanical motion of switched reluctance motor was established. Secondly, an improved sliding mode controller which is based on synchronous signal transmission technology was designed by analyzing the reason of large torque ripple of switched reluctance motor, and the stability of the system was proved. Finally, simulation is used to verify the effectiveness of the control strategy.Compared with the traditional PID (Proportional Integral Differential) control algorithm, this control technology not only suppresses the SRM torque ripple effectively , but also makes the sliding mode controller output the precise target electromagnetic torque quickly by increasing the control variables. The results of research indicate that this design can not only restrain the torque ripple effectively, but also adjust the convergence speed and overshoot of the controller by adjusting the design parameters.

This paper presents the design, analysis and comparative study of three different configurations of Switched Reluctance Motor (SRM) suitable for In-wheel application in Electric Vehicles. C-core stator with dual rotor SRM, C-core stator with disk-type segmented rotor SRM and Dual gap inner segmented rotor SRM are designed and compared for the same stator/rotor pole, supply current, current density and outer diameter. The significant performance indices of an electric motor for an in-wheel application, such as torque ripple, torque per unit active weight and torque per unit active volume, are considered for analysis. 3D Finite Element Analysis (FEA) of the machines is performed using the software MagNet 7.5 due to the axial field distribution of the configurations. The best among the three configurations is fabricated and experimental results are presented. [ABSTRACT FROM AUTHOR]

In this paper, the impact of parameter matching on the steady-state performance of permanent magnet-assisted synchronous reluctance motors (PMaSynRM) under vector control is analyzed and discussed. First, based on the mathematical model of motors under the maximum torque per ampere (MTPA) control strategy, an analysis is conducted concerning two main parameters, i.e., the matching relationship between the back electromotive force (back-EMF) and the saliency ratio. The impact of these two parameters on the operational status of the motor is investigated. Then, the motor's voltage operating conditions are examined, and the operating curve under minimum voltage is derived. Furthermore, in the overvoltage region under the MTPA control strategy, the operation of the motor under the maximum torque per voltage (MTPV) control strategy is explored. This analysis illuminated the patterns of influence exerted by the back-EMF and the saliency ratio on the motor's voltage operating condition. Between these two control strategies, there remains scope for the motor to operate at its limits. An enhanced understanding of the effects of the back-EMF and saliency ratio within this range on motor performance was achieved, resulting in the optimal matching curve for the back-EMF and saliency ratio. Finally, a 45 kW PMaSynRM was designed, prototyped, and tested to validate the correctness of the design techniques, with the motor achieving IE5 efficiency. [ABSTRACT FROM AUTHOR]

The performance of drives with switched reluctance motors (SRMs) depends on magnetic materials used in their construction which influence static parameters such as inductance and electromagnetic torque profiles. The paper deals with simulations of switched reluctance motors in the finite element method and their comparison with measurements. Two kinds of switched reluctance motors were analysed, the modified Emerson Electric motor with a laminated steel core and a prototype, the one with a magnetic core made of iron-based powder composite materials. In the first part of the research, magnetization curves of magnetic materials were measured for static and dynamic conditions with 50 Hz. Next, simulations and measurements of inductance and developed torque were compared and analysed. In the last part of the research, simulations of magnetic flux density in motors were conducted. As the result of the research, it occurred that the simulations and measurements are quite close and two kinds of motors exhibit similar performance.

In this article, a wireless resolver is proposed and implemented for wireless switched reluctance (SR) motors, which can detect the rotor position and transfer the information to the primary side without involving any battery storage or active components at the secondary side. The key is to integrate wireless power transfer (WPT) into a variable reluctance resolver to detect and transmit the rotor position. Compared with previous wireless SR motors adopting the Hall effect position encoder and Bluetooth communication, the robustness is highly improved, and the communication delay caused by the connection interval can be solved. Therefore, the proposed system takes the definite advantages of better dynamic performance and sealability. Besides, there is no need to specially design the SR motor, as all existing SR motors and other similar kinds of motors can readily employ this wireless resolver. An experimental prototype has been built for verification, which works well from 100 to 900 rpm with 20 mm WPT distance, and the additional power for position detection can be limited to 1.05 W while the motor consumes 54 W. [ABSTRACT FROM AUTHOR]

This research presents an improved direct instantaneous torque controller (DITC) for switched reluctance motors (SRMs). It incorporates a novel adaptive real-time commutation mechanism. The proposed method can effectively enhance the torque profile and efficiency of the machine by proper real-time adjustment of both the turn-on and the turn-off angles. First, an initial value of the turn-on angle is selected to achieve the highest torque generation capability. Then, with a real-time adjustment around the pre-selected initial angle, the instantaneous torque error can be further compensated. Hence, the torque ripple is minimized. Regarding the turn-off angle, an initial value is selected to satisfy the minimum required conduction angle of SRM. Then, this value is continuously adjusted at each electrical cycle by utilizing a phase current detector to force the outgoing phase current to decay to a less effective value before the negative slope of the inductance profile. Therefore, this prevents serious negative torque generation. The proposed strategy fully utilizes the torque generation capability of the motor with a minimized torque ripple, besides the phase currents, are generated in optimal conduction range to enhance the motor efficiency. The simulations and experiments have been carried out on a 3-phase 750 W 12/8 SRM to validate the proposed method's feasibility and effectiveness. [ABSTRACT FROM AUTHOR]

To reduce the influence of time delay on the tracking performance of a direct-drive motion control system, this paper concentrates on stability analysis and cooperative position tracking control issues for the dual linear switched reluctance motors (LSRMs) system with network-induced time delays. The closed-loop network control system (NCS) is constructed by modeling random and bounded network-induced time delays existing in forward and feedback channels as a discrete-time Markov chain. Incremental time delay information is introduced in Lyapunov functional analysis to satisfy the high-precision movement of master and secondary motors and improve the system control performance. The time delay compensation method is proposed to compensate for the damage to the networked control system caused by random delay. With Lyapunov stability theory and LMI are applied, stability and stabilization conditions with less computational complexity and low conservatism are obtained based on incremental time delay information insertion. Finally, the numerical simulation and the experimental platform of the motor control system are built. Simulation and experiment results demonstrate that the networked control strategy can compensate the negative impact of delay on the tracking performance of LSRMs based motion control system. • A Lyapunov functional with time delay is constructed, and the stability condition of the proposed networked dual LSRMs system is analyzed. • Combining Lyapunov theory, linear matrix inequality technology and Markov stochastic process, the time delay compensation controller for the proposed networked dual LSRMs is designed. • Incremental delay compensation and Wirtinger-based inequality are used for stability analysis and control strategy to obtain lower computational complexity and conservativeness. • The networked dual LSRMs system with time delay is constructed both on the simulation and physical experiment platform, and the networked control strategy based on time delay compensation is verified from the numerical simulation and physical experiment. [ABSTRACT FROM AUTHOR]

Abstract Here, the authors propose two new Permanent Magnet (PM) embedded linear switched reluctance motors; one is a modular linear hybrid reluctance motor (MLHRM), and the other one is a segmental linear hybrid reluctance motor (SLHRM). Both structures employ PMs between the side teeth of the modules/segments. The main contribution of the PMs is to increase the air‐gap flux density, which results in an enhanced thrust, and decrease the magnetic saturation in iron parts. The magnetic equivalent circuit model is used to demonstrate the positive effect of inserting PMs in the MLHRM and SLHRM compared to their PMless counterparts. The optimal pole number and design procedure are illustrated. The simulation results are obtained in terms of static thrust, flux linkage, flux density distributions, and steady‐state current and thrust. The results show that the proposed MLHRM and SLHRM offer a higher thrust and lower current compared to their PMless form. Also, the PMs decrease the root mean square (RMS) current under the steady‐state performance of the motors, in which a higher thrust is produced with a lower RMS current. Finally, the MLHRM and SLHRM are fabricated and the test results are obtained and compared with the simulations, which illustrate a satisfactory agreement.

The design and analysis of synchronous reluctance motor (SynRM) with a distributed type winding is an alternative to replace the permanent magnet synchronous motors (PMSM), which is commonly used in electric vehicle applications. The use of a SynRM eliminates the need for permanent magnets (PMs), reducing the dependence on rare earth materials and potentially lowering costs. In this paper, there are two approaches: a new approach of step-skewing rotor (SSR) is proposed to improve eletromagnetic parameters such as minimization of the active volume, maximization of the output power and reduction of the torque ripple of the SynRM. Then, a finite element technique is developed to analyse and simulate the distribution of magnetic flux and map efficiency of the proposed SynRM. Additionally, the paper has also investigated the distribution of temparature and machnical stress in the region of flux barries of the rotor.

In this paper, the impact of parameter matching on the steady-state performance of permanent magnet-assisted synchronous reluctance motors (PMaSynRM) under vector control is analyzed and discussed. First, based on the mathematical model of motors under the maximum torque per ampere (MTPA) control strategy, an analysis is conducted concerning two main parameters, i.e., the matching relationship between the back electromotive force (back-EMF) and the saliency ratio. The impact of these two parameters on the operational status of the motor is investigated. Then, the motor’s voltage operating conditions are examined, and the operating curve under minimum voltage is derived. Furthermore, in the overvoltage region under the MTPA control strategy, the operation of the motor under the maximum torque per voltage (MTPV) control strategy is explored. This analysis illuminated the patterns of influence exerted by the back-EMF and the saliency ratio on the motor’s voltage operating condition. Between these two control strategies, there remains scope for the motor to operate at its limits. An enhanced understanding of the effects of the back-EMF and saliency ratio within this range on motor performance was achieved, resulting in the optimal matching curve for the back-EMF and saliency ratio. Finally, a 45 kW PMaSynRM was designed, prototyped, and tested to validate the correctness of the design techniques, with the motor achieving IE5 efficiency.

Currently, there are few systematic position control parameter optimization methods for planar switched reluctance motors (PSRMs); how to effectively optimize the control parameters of PSRMs is one of the critical issues that needs to be urgently solved. Therefore, a nonlinear dynamic model-based position control parameter optimization method of PSRMs is proposed in this paper. First, to improve the accuracy of the motor dynamics model, a Hammerstein–Wiener model based on the BP neural network input–output nonlinear module is established by combining the linear model and nonlinear model structures so that the nonlinear and linear characteristics of the system are characterized simultaneously. Then, a position control parameter optimization system of PSRMs is developed using the established Hammerstein–Wiener model. In addition, with a self-designed simulated annealing adaptive particle swarm optimization algorithm (SAAPSO), the position control parameter optimization system is performed offline iteratively to obtain the optimal position control parameters. Simulations and experiments are carried out and the corresponding results show that the optimal position control parameters obtained by the proposed method can be directly applied in the actual control system of PSRMs and the control performance is improved effectively using the obtained optimal control parameters. [ABSTRACT FROM AUTHOR]

The goal of this article is to develop a new topology optimization framework that can secure the manufacturability of the synchronous reluctance motors (SynRMs) with multiple iron webs and bridges while satisfying the required electromagnetic and mechanical performances. In the SynRM, multiple iron webs and bridges are crucial to achieve a higher torque and a structural safety. A minimum thickness of the web and bridge should also be guaranteed to achieve manufacturability. To acquire the optimal SynRM that can satisfy the above characteristics, a two-stage topology optimization framework is proposed with an individual filtering-and-penalization scheme. This proposed scheme can individually control the number and thickness of multiple iron webs and bridges in the rotor to obtain the manufacturable and structurally safe SynRMs. For the abovementioned purpose, topology optimization is formulated to minimize a torque ripple while satisfying the desired average torque, structural compliance, and a rotational moment of inertia. Average torque and structural compliance are evaluated by performing the electromagnetic and structural finite element analyses, respectively, at each iteration of topology optimization. Here, design-dependent loads are considered in the radial and circumferential directions to reflect a high-speed rotation. Through investigating the optimized SynRM designs with various filter radii, the relationship among the torque, structural pattern, and stress distribution is examined. Finally, the experimental results with the manufactured prototypes validate the feasibility and potential of the proposed design method. [ABSTRACT FROM AUTHOR]

This paper presents the design, analysis and comparative study of three different configurations of Switched Reluctance Motor (SRM) suitable for In-wheel application in Electric Vehicles. C-core stator with dual rotor SRM, C-core stator with disk-type segmented rotor SRM and Dual gap inner segmented rotor SRM are designed and compared for the same stator/rotor pole, supply current, current density and outer diameter. The significant performance indices of an electric motor for an in-wheel application, such as torque ripple, torque per unit active weight and torque per unit active volume, are considered for analysis. 3D Finite Element Analysis (FEA) of the machines is performed using the software MagNet 7.5 due to the axial field distribution of the configurations. The best among the three configurations is fabricated and experimental results are presented.

The switched reluctance motor (SRM) benefits from its magnet-free nature, robust construction, low cost, flexible controls, and the ability to operate in harsh environments such as high temperatures and high pressure. It has received increasing attention for all-electric or multi-electric aircraft systems and electric vehicles (EVs) as compared with permanent magnet synchronous motors (PMSM) and other AC motors in some required high reliability and fault tolerance applications. However, the SRM is prone to considerable wind resistance due to the convex pole structure of the rotor during high-speed rotation, high torque ripple, and also vibration noise. Thus, it is currently a trending topic to develop special SRMs, tailored with high reliability and fault tolerance. Recent research demonstrates several promising feasible solutions to reduce torque ripples and enhance torque density and power factors, including changing topology of SRM, using advanced control methods, as well as different winding configurations. Among these options, the segmented switched reluctance motor (SSRM), as a deformation of the conventional topology, is shown to be capable of effectively optimizing the torque performance. Motivated by this advance, this paper aims to present a comprehensive literature review on the SSRM, first illustrating the development of the topology of the SRM, then providing a description as well as a classification according to the topology of the SSRM. In particular, we focus on the evolution of various kinds of segmental topology and improvement measures. Then, we discuss the performance, advantages, and disadvantages of various types of structures in terms of their electromagnetic aspects and their applications. Eventually, several promising future trends and application prospects of the SSRM are prospected, with the aim of shedding light on further research. In sum, the key contribution of this paper is to provide a valuable basis for detailed analyses of the structure and electromagnetic design of the SSRM that are expected to benefit future research. [ABSTRACT FROM AUTHOR]

In electric vehicle (EV) applications, hybrid excitation of switched reluctance motors (HESRMs) are gaining popularity due to their advantages over other EV motors. The benefits include control flexibility, simple construction, high torque/power density, and the ability to operate over a broad speed range. However, modern HESRMs are constructed by increasing the air gap flux density with permanent magnets (PMs) in the excitation system in order to generate more electromagnetic torque. This study aims to investigate a new topology for increasing the torque capabilities of HESRM without the use of permanent magnets (PMs) or other rare-earth components. This paper provides a comprehensive evaluation of the static and dynamic characteristics, software analysis using the Ansys 2D finite element method (FEM), and an experimental demonstration of the real-time motor with an advanced control strategy in MATLAB/Simulink. Our simulation and experimental results for a machine with 12/8 poles and a machine rating of 1.2 kW indicate that the HESRM designed without PMs has greater torque capability and efficiency than the conventional SRM. The proposed HESRM without PMs has a high torque/power density and a higher torque per ampere across the entire speed range, making it suitable for EV applications. [ABSTRACT FROM AUTHOR]

Due to their advantages, switched reluctance motors (SRMs) are interesting solutions for electric vehicle (EV) propulsion. However, they have the main drawback of high torque ripple. This paper develops a universal torque control (UTC) technique for SRM that can fulfill all vehicle requirements under a wide range of speeds. The developed UTC involves two different control techniques. It utilizes the direct instantaneous torque control (DITC) strategy in a low speed region, and the average torque control (ATC) strategy in high speeds. The selection of DITC and ATC is made based on their performance regarding torque ripple, torque/current ratio, and efficiency. Moreover, a novel transition control between the two control techniques is introduced. The results show the ability of the proposed UTC to achieve vehicle requirements while obtaining all the benefits of torque control over the possible range of speeds. The proposed UTC provides the best performance regarding minimum torque ripple, maximum torque/current ratio, and maximum efficiency over the whole speed range. The transition control achieves a smooth operation without any disturbances. The transition control helps to simplify the overall control algorithm, aiming to have a feasible and practical UTC without a complicated control structure. [ABSTRACT FROM AUTHOR]

Today, the majority of the commercial electrified vehicles use Interior Permanent Magnet Motors (IPMSMs) for propulsion. An IPMSM can deliver high starting torque and high efficiency in the low- and medium-speed operation, which makes it attractive for propulsion applications. However, IPMSMs generally utilize rare-earth permanent magnets and there are growing concerns about the price volatility and supply chain of these materials. Switched Reluctance Motors (SRMs) can potentially replace IPMSMs in various applications including propulsion. An SRM has a simple and low-cost construction, and it can provide reliable operation at high-speed and high-temperature conditions. Compared to IPMSMs, SRMs radiate considerably higher acoustic noise, which have historically hindered their widespread acceptance. Various approaches to mitigate acoustic noise and vibration at the source level have already been explored in the literarture by improving the electromagnetic design and current control. This paper explores multiple noise and vibration mitigation methods that can be applied at the transmission stage. First, the noise comparison between the Internal Combustion Engine (ICE) and SRMs is discussed, and then the methods used for ICEs are presented for their applicability to SRMs.

Precise estimation of position is essential in the control of switched reluctance motors (SRMs). Traditionally, the intersection of the adjacent inductance can be utilized to estimate the rotor position, however, magnetic saturation brings about variations in the intersection position when the motor is operated at heavy load. To solve this problem, this paper develops a sensorless position estimation strategy considering magnetic saturation and the embrace design. Sensorless control approaches can be chosen interchangeably according to the characteristics of the intersection. Rotor position estimation is achieved by employing six typical inductance positions. No additional position sensor and other detection devices are required. Through simulation and experiment, the feasibility and validity of the proposed position estimation method are verified. The proposed sensorless method is verified for acceleration, constant operated state, and load mutation.

Special attention has been paid to two-phase switched reluctance motors (SRMs) as they have fewer power electronics components compared to three- or multi-phase ones. However, their main drawbacks are the lack of starting torque and a predetermined direction of rotation. This paper proposes a new self-starting technique for two-phase SRMs, which has superiorities over the previous approaches. In the proposed topology, the flux paths are shorter, and thus the required magnetomotive force is smaller, which reduces losses. The design procedure is explained. Two- and three-dimensional finite element method (FEM) is employed in the analysis. Also, the motor is prototyped, and two test setups for torque-angle measurement and control study are used. The dynamic behavior of the motor is studied applying single-pulse control and current hysteresis control strategies. The experimental results confirm the results obtained by FEM. Both simulation and experiment results confirm that the proposed topology offers higher efficiency, higher mean torque, and better dynamic behavior compared to two conventional SRMs. [ABSTRACT FROM AUTHOR]

This paper presents a new sensorless control strategy with the fault-tolerant ability for switched reluctance motors (SRMs). Nowadays, many rotor position detection methods are utilized, but most of them increase the system cost due to the additional hardware or complex calculations. To address this problem, various methods of using phase inductance to estimate the rotor position and speed have been proposed. However, the traditional inductance detection method will cause signal distortion due to the presence of interference signals and the unbalanced phase inductance. In particular, the turn-ON angle is advanced. To further improve the stability of the control system, the interference signals are eliminated via establishing the reference time of the inductance characteristic point and the error band in this work. When the position signal disappears, the inductance characteristic points of adjacent phases will be adopted for signal compensation to realize fault-tolerant control. Finally, an SRM drive system is used to verify the effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

Recently, model-based predictive current control (MB-PCC) has been presented as a good alternative to classical control algorithms in terms of simplicity and performance reliability. However, MB-PCC suffers from the high dependence on system parameters, which may deteriorate its performance under parameters variations. On the other hand, synchronous reluctance motors (SynRMs) are susceptible to suffer from inductances variations due to the magnetic saturation. Accordingly, in this article a new model-free predictive current control of SynRMs based on a recurrent neural network (RNN-PCC) is developed and proposed. The proposed RNN-PCC relies on the identification of the SynRM currents without considering any parameters. Simulation and experimental results show that both RNN-PCC and MB-PCC have similarly excellent dynamics, while better control performance and tracking errors can be achieved thanks to the proposed RNN-PCC. [ABSTRACT FROM AUTHOR]

To improve the endurance and charging flexibility of electric vehicle battery packs, this paper proposes a multi-battery block module (MBM) topology for four-phase switched reluctance motors (SRMs), which not only allows flexible electric vehicle operation, but also achieves fast demagnetization and excitation. By integrating the multi-battery block module and photovoltaic (PV) panel into an asymmetrical half-bridge (AHB) converter, the MBM topology is designed to supply a multilevel bus voltage for the SRM drive. To improve the endurance of battery packs, a PV panel is also added to the topology to charge battery packs when the system is stationary. According to the different operation requirements, multiple power supply modes and charging modes can be realized by controlling the power devices in the proposed MBM topology. The simulation results based on the MATLAB/Simulink platform and the experimental results on a four-phase 8 / 6 switched reluctance motor verify the effectiveness of the proposed design.

Existing research on geometry optimization of switched reluctance motor (SRM) using machine learning algorithms has focused only on the machine’s static characteristics. The dynamic characteristics, however, are critical to improve the SRM performance, particularly at high speeds. This paper introduces an advanced optimization method utilizing a supervised learning algorithm to act as a surrogate model for both static and dynamic characteristics of the SRM. In this work, back-propagation neural network (BPNN) is applied to map out the SRM geometrical parameters, stator and rotor pole arc angles and their dynamic performance metrics such as average torque and torque ripples. To capture the training data, finite element analysis (FEA) and MATLAB Simulink models are implemented to study the static and dynamic characteristics of the considered 6/14 SRM. Levenberg-Marquardt is applied to train the BPNN. The results of the proposed optimal design candidates are verified using FEA and MATLAB simulations, confirming the effectiveness of the optimal design. The optimal design improves the average torque by around 2% and reduces the torque ripples by around 24%. Moreover, the proposed method significantly decreases the computational overhead.

Low-cost photovoltaic-powered elevators (PVPEs) have gained ever-increasing attention in the last few years for their advantages in terms of renewable energy and low maintenance costs after installation. In this paper, four highstep-up DC-DC converters for low-voltage sources such as solar photovoltaic, fuel cells, and battery banks are proposed. Their performances are evaluated in terms of optimal capability and high reliability. Among the four proposed architectures, the bootstrap converter is selected for its ability to restrict losses and other redundant parameters. The proposed converter drives the inverter-driven switched reluctance motor (SRM) assembly through a directly coupled method, which eliminates the need for battery banks while aiding in cost reduction. The prototype model is implemented, and results are validated, showing promising performance and thus being very efficacious for application to low-cost PVPEs. [ABSTRACT FROM AUTHOR]

The switched reluctance motor (SRM) benefits from its magnet-free nature, robust construction, low cost, flexible controls, and the ability to operate in harsh environments such as high temperatures and high pressure. It has received increasing attention for all-electric or multi-electric aircraft systems and electric vehicles (EVs) as compared with permanent magnet synchronous motors (PMSM) and other AC motors in some required high reliability and fault tolerance applications. However, the SRM is prone to considerable wind resistance due to the convex pole structure of the rotor during high-speed rotation, high torque ripple, and also vibration noise. Thus, it is currently a trending topic to develop special SRMs, tailored with high reliability and fault tolerance. Recent research demonstrates several promising feasible solutions to reduce torque ripples and enhance torque density and power factors, including changing topology of SRM, using advanced control methods, as well as different winding configurations. Among these options, the segmented switched reluctance motor (SSRM), as a deformation of the conventional topology, is shown to be capable of effectively optimizing the torque performance. Motivated by this advance, this paper aims to present a comprehensive literature review on the SSRM, first illustrating the development of the topology of the SRM, then providing a description as well as a classification according to the topology of the SSRM. In particular, we focus on the evolution of various kinds of segmental topology and improvement measures. Then, we discuss the performance, advantages, and disadvantages of various types of structures in terms of their electromagnetic aspects and their applications. Eventually, several promising future trends and application prospects of the SSRM are prospected, with the aim of shedding light on further research. In sum, the key contribution of this paper is to provide a valuable basis for detailed analyses of the structure and electromagnetic design of the SSRM that are expected to benefit future research.

This paper proposes a modelling technique for Synchronous Reluctance Motors (SynRMs) based on a generalized Magnetic Equivalent Circuit (MEC). The proposed model can be used in the design of any number of stator teeth, rotor poles, and rotor barrier combinations. This technique allows elimination of infeasible machine solutions during the initial machine sizing stage, resulting in a lower cohort of feasible machine solutions that can be further optimized using finite element methods. Therefore, saturation effects, however, are not considered in the modelling. This paper focuses on modelling a generic structure of the SynRM in modular form and is then extended to a full SynRM model. The proposed model can be iteratively used for any symmetrical rotor pole and stator teeth combination. The developed technique is applied to model a 4-pole, 36 slot SynRM as an example, and the implemented model is executed following a time stepping strategy. The motor characteristics such as flux distribution and torque of the developed SynRM model is compared with finite elemental analysis (FEA) simulation results. [ABSTRACT FROM AUTHOR]

As electric vehicles (EVs) continue to acquire prominence in the transportation industry, improving the outcomes and efficiency of their propulsion systems is becoming increasingly critical. Switched Reluctance Motors (SRMs) have become a compelling option for EV applications due to their simplicity, magnet-free design, robustness, and cost-effectiveness, making them an attractive choice for the growing EV market. Despite all these features and compared to other electrical machines, SRMs suffer from some restrictions, such as torque ripple and audible noise generation, stemming from their markedly nonlinear characteristics, which affect their productivity and efficiency. Therefore, to address these problems, especially the torque ripple, it is crucial and challenging to enhance the performance of the SRM drive system. This paper proposed a comprehensive review of torque ripple minimization strategies of SRMs in EV applications. It covered a detailed overview and categorized and compared many strategies, including two general categories of torque ripple mitigation encompassing optimization design topologies and control strategy developments. Then, focused on control strategy improvements and divided them into torque and current control strategies, including the sub-sections. In addition, the research also provided an overview of SRM fundamental operations, converter topologies, and excitation angle approaches. Last, a comparison between each method in torque control and current control strategies was listed, including the adopted method, features, and drawbacks. [ABSTRACT FROM AUTHOR]

Switched reluctance motors (SRMs) face challenges in achieving high performances in terms of the power factor, torque per ampere, and torque ripples. Although several parameters impact their performance, magnetic saliency has a significant impact. This paper presents a study on the influence of the saliency ratio on the performance of switched reluctance motors. A detailed design procedure for a mid-drive electric motor for a high-performance electric bike is presented. A systematic methodology is adopted to estimate the power rating for desired vehicle performance while considering the vehicle’s mechanical and aerodynamic parameters. Additionally, the paper discusses and analyzes the design of two SRM motor configurations with different rotor poles (6/4 and 6/10) while performing magnetostatic analysis for generated torque validation. A parametric study is performed on the 6/10 SRM design for further improvement in the torque profile while keeping the same fill factor and electrical loading. Furthermore, the transient analysis in Ansys Maxwell 2D for both SRMs confirms the designed performance. The results shows that the SRM with higher rotor poles (6/10) is a better choice.

In traditional analytical method (AM), the magnetic saturation is always ignored to simplify the calculation process. However, synchronous reluctance motors (SynRMs) often operate around saturation point to achieve higher torque density. Therefore, a new AM is proposed, in which the saturation of stator iron has been considered. The key of the proposed method includes a saturation factor, and an iterative method is adopted to compute the saturation factor in the SynRM by increasing the air-gap length. Especially, the proposed AM can be applied to a SynRM even with shifted-asymmetrical-salient-poles. In the process of AM, the expression of stator magnetomotive force (MMF) is built firstly. Additionally, the air-gap density including slotting effect and salient-poles is calculated. Then, the rotor MMF under saturation of the stator iron is obtained. Therefore, the precision of the instantaneous torque can be improved significantly. Eventually, by the verification of finite elements method (FEM) and experiments, the torque performance of SynRMs with shifted asymmetrical rotor can be predicted accurately by the proposed AM.

Abstract The present work aims at the application of different optimization strategies in the electromagnetic analysis of the Variable Reluctance Motor (VRM) through Finite Element (FE) simulation. Two case studies are investigated: the first one aims to optimize the geometry and electrical characteristics of windings of a single-phase VRM 6/6, minimizing copper losses; the second aims to optimize a restricted set of geometric parameters of a 4- phase VRM 8/6, maximizing the flux linkage in the phase coils per unit volume of magnetic core. In this way, by using the Finite Element Method (FEM), the results from the Differential Evolution (DE) and Particle Swarm Optimization (PSO) algorithms will be compared and highlighted. Then, the magnetic flux densities of the motors are analyzed before and after the optimization. The results obtained show good efficiency of the algorithms, since the objective functions were satisfied with respect to the reference models.

Featured in low-speed and high-torque operation, outer-rotor switched reluctance motors (OSRMs) have the potential to be widely deployed in low-speed commuter and logistics vehicle applications. In this paper, a five-phase OSRM and the control method featuring torque ripple reduction has been proposed, which can be applied as the wheel hub motor in the electric vehicles. The simulation was carried out to analyze the OSRM operation. The electromagnetic characteristics of single-phase and two-phase hybrid excitation mode, as well as step current excitation mode, were compared and analyzed. To solve the problem of the large torque ripple of OSRMs under traditional excitation modes, the torque ripple suppression method based on step current excitation was also studied. The experiment design, including motor start-up control, speed control, and torque ripple reduction, are presented to verify the system torque ripple mitigation method. [ABSTRACT FROM AUTHOR]

Analytical modeling (AM) of the magnetic field for axial-flux switched reluctance motors (AFSRMs), considering 3-D features and nonlinear saturation effects, remains to be a knotty problem. This article proposes a quasi-3-D nonlinear AM method to predict magnetic field distributions and electromagnetic performances of an AFSRM. First, the harmonic modeling (HM) technique is applied to obtain the spatiotemporal distribution characteristics of the axial and tangential magnetic flux density at the mean radius. Second, the nonlinearity of the soft magnetic material in teeth is considered by an adaptive convergence rate algorithm. Finally, a radial dependence function is formulated to extend the solution of the annular Section to any point in the 3-D space of the AFSRM. To confirm the accuracy of the proposed method, the analytical solutions of magnetic flux density and electromagnetic torque have been compared with FEM simulation results. Meanwhile, an additional validation has been done for the stability of this nonlinear AM method under severe saturation conditions. Finally, the reasonable selection of the harmonic truncation order number has been discussed to reach a good balance between accuracy and time cost. The quasi-3-D nonlinear AM method can consider the curvature and edge effect, as well as the saturation effect effectively, which is suitable for performance predictions and parametric studies of AFSRMs. [ABSTRACT FROM AUTHOR]

With high surrounding temperatures, winding resistance increases and thus lowers the operational efficiency of a motor. To meet the large application requirements and conform with the ever-increasing energy-efficiency regulations for pump equipment in the metals industry, consistent efforts have focused on producing single-phase motors that can deliver superior performance at a low cost. Because the steady-state rotational speed is synchronized and no driver circuit is required, a direct-on-line synchronous reluctance motor is a potentially viable alternative to the commonly adopted induction motors. Its inherently simple structure and comparably low operational speed necessitate a challenging structural design for accomplishing the high-efficiency objectives of pump applications. These challenges and their potential solutions are reported in detail. By employing a systematic design scheme and including thermal concerns of the performance, a competitive high-efficiency single-phase direct-on-line synchronous reluctance motor for pump applications in various metal industry equipment was offered. [ABSTRACT FROM AUTHOR]

In this paper, a finite-control-set model predictive direct torque control (FCS-MPDTC) method is proposed to reduce the torque ripple of a segmented switched reluctance motor (SSRM) at the low-speed stage. Firstly, the prediction dynamic model is established, and the phase torque can be predicted by detecting phase current and rotor position signals. Then, the principle of power converter and selection of voltage vectors are introduced and presented. Considering torque ripple reduction, flux tracking performance and copper losses reduction, the cost function with phase torque, the amplitude of flux linkage and phase current, is established to select optimal voltage vector to control the power converter. In addition, the torque sharing function (TSF) is employed to distribute total torque to phase torque for further torque ripple reduction. Finally, the direct torque control (DTC) is selected as the comparison method, performance of MPDTC is verified by simulation and experiment results. It can be found that the proposed MPDTC can achieve lower torque ripple and copper losses, and high robustness. [ABSTRACT FROM AUTHOR]

Currently, there are few systematic position control parameter optimization methods for planar switched reluctance motors (PSRMs); how to effectively optimize the control parameters of PSRMs is one of the critical issues that needs to be urgently solved. Therefore, a nonlinear dynamic model-based position control parameter optimization method of PSRMs is proposed in this paper. First, to improve the accuracy of the motor dynamics model, a Hammerstein–Wiener model based on the BP neural network input–output nonlinear module is established by combining the linear model and nonlinear model structures so that the nonlinear and linear characteristics of the system are characterized simultaneously. Then, a position control parameter optimization system of PSRMs is developed using the established Hammerstein–Wiener model. In addition, with a self-designed simulated annealing adaptive particle swarm optimization algorithm (SAAPSO), the position control parameter optimization system is performed offline iteratively to obtain the optimal position control parameters. Simulations and experiments are carried out and the corresponding results show that the optimal position control parameters obtained by the proposed method can be directly applied in the actual control system of PSRMs and the control performance is improved effectively using the obtained optimal control parameters.